Otosclerosis has an unequivocal hereditary predisposition although the exact nature of the genetic transmission has not been delineated. In some cases otosclerotic lesions are histologically identical to the otic capsule lesions observed in osteogenesis imperfecta. Some forms of osteogenesis imperfecta have been causatively linked to genetic defects in type I collagen. Genetic defects in milder forms of hereditary chondrodysplasias have been causatively linked to the gene for type II collagen. In this study we propose to evaluate the linkage between otosclerosis and type I and type II collagen gene restriction fragment length polymorphisms in affected family members with well-established otosclerosis. If these candidate genes are found not to be linked to clinical otosclerosis, attempts will be made to identify the otosclerotic gene locus or loci by linkage analysis to other gene segment markers. In addition experiments will be conducted to continue investigation of a possible defective measles virus presence in otosclerosis. These studies will focus on the use of polymerase chain reaction techniques to establish the presence of measles virus nucleic acids within affected temporal bone sections.